<!DOCTYPE html>
<html>
<head>
<script>

function boom()
{
  window.getSelection().removeAllRanges();
  var r = document.createRange();
  r.setStart(document.getElementById("x"), 1);
  r.setEnd(document.getElementById("y"), 0);
  window.getSelection().addRange(r);
  document.execCommand("insertorderedlist", false, null);
}

</script>
</head>

<body onload="boom();"><div id="x" contenteditable="true">a</div><div id="y" contenteditable="true"></div></body>
</html>
